A well proven method for creating a 3D image is to cause a viewer to see different perspective views of a scene with each eye. One way to do this is to display two differently polarized images on a screen, and for the viewer to wear corresponding polarizing filters on each eye.
An autostereoscopic display or a three dimensional (3D) display may be implemented using an aperture or slit array in conjunction with a two dimensional (2D) display to display a 3D image. The principle of the device is that when looking at a 2D image through a slit array, the slit array separated from the screen by a distance, then the viewer sees a different part of the 2D image with each eye. If an appropriate image is rendered and displayed on the 2D display, then a different perspective image can be displayed to each eye of the viewer without necessitating them to wear filters over each eye.
One important parameter which governs quality in most 3D display technology, is bandwidth, defined as the amount of data presented by a 3D display. To achieve large depth with high resolution over a wide viewing area, a large bandwidth is usually required.
Embodiments of the invention demonstrate ways in which bandwidth limitations of autostereoscopic display apparatus may be overcome in order that high resolution 3D images may be displayed.
The invention disclosed herein may be implemented in the scanning slit time-multiplexed system described in PCT application PCT/IB2005/001480. However, the invention may also be used in conjunction with other display systems.
The scanning slit system creates the 3D effect by showing different pictures to different locations in front of the display at high speed. It achieves this by combining a high frame rate 2D display with a shutter. The shutter is synchronised with the display and ensures that different portions of the 2D display are visible only from specific locations. The left image in FIG. 1 shows how a viewer looking through a narrow slit will see two distinct regions, one for each eye. To create a 3D display from this simple slit system, the slit must shift laterally sufficiently quickly so that a viewer sees the scanning shutter as a transparent window. If all the slits are updated quickly enough to be perceived as flicker-free, a viewer will see the full resolution of the underlying 2D display from any position. The 2D display shows different images synchronised with the opening of slits in the shutter, as shown in the right image in FIG. 1.